The advent of computers, interactive electronic communication, the Internet, and other advances in the digital realm of consumer electronics have resulted in a need for digital data encoding techniques that are accurate and efficient.
Fixed length encoding is one type of data encoding technique that is commonly used to store and transmit digital data. In fixed length encoding, a number of digital bit patterns of fixed lengths are used to define the characters or symbols of a written language, thus allowing digital devices to store, process, and communicate character-oriented information.
Common fixed length encoding schemes include, but are not limited to, the American Standard Code for Information Interchange (ASCII), extended-ASCII, Extended Binary-Coded Decimal Interchange Code (EBCDIC), and Unicode. In ASCII, for example, a seven bit encoding scheme is used to represent ninety-four printable characters including letters, numbers, and punctuation symbols in addition to thirty-four control characters and other “special characters.” In extended-ASCII, an eighth bit is added to the encoding scheme to facilitate representation of 128 additional symbols.
Fixed length encoding is used to store and transmit all types of data. For example, fixed length encoding is often used to store and transmit large compilations of text and/or numbers, such as names, telephone numbers, credit card numbers, social security numbers, and other identification numbers.
However, fixed length encoding is inherently inefficient when used to encode certain types of data. For example, when decimal data (i.e., data that includes the digits between 0 and 9) is stored using extended-ASCII encoding, fifty percent or more of the consumed storage medium may be wasted on bits that are not necessary to represent the data. Moreover, the encoding of large data files often requires large storage media and time-consuming data processing.